From: Andreas Pape <apape@xxxxxxxxxxxxxx>
[ Upstream commit d1c442019594692c64a70a86ad88eb5b6db92216 ]
Setting pointer and afterwards checking for wraparound leads
to the possibility of returning the inconsistent pointer position.
This patch increments buffer pointer atomically to avoid this issue.
Fixes: e7f73a1613567a ("ASoC: Add dmaengine PCM helper functions")
Signed-off-by: Andreas Pape <apape@xxxxxxxxxxxxxx>
Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1664211493-11789-1-git-send-email-erosca@xxxxxxxxxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
sound/core/pcm_dmaengine.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/sound/core/pcm_dmaengine.c b/sound/core/pcm_dmaengine.c
index 5b2ca028f5aa..494ec0c207fa 100644
--- a/sound/core/pcm_dmaengine.c
+++ b/sound/core/pcm_dmaengine.c
@@ -133,12 +133,14 @@ EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_set_config_from_dai_data);
static void dmaengine_pcm_dma_complete(void *arg)
{
+ unsigned int new_pos;
struct snd_pcm_substream *substream = arg;
struct dmaengine_pcm_runtime_data *prtd = substream_to_prtd(substream);
- prtd->pos += snd_pcm_lib_period_bytes(substream);
- if (prtd->pos >= snd_pcm_lib_buffer_bytes(substream))
- prtd->pos = 0;
+ new_pos = prtd->pos + snd_pcm_lib_period_bytes(substream);
+ if (new_pos >= snd_pcm_lib_buffer_bytes(substream))
+ new_pos = 0;
+ prtd->pos = new_pos;
snd_pcm_period_elapsed(substream);
}
--
2.35.1
